Control method for laundry treatment apparatus

ABSTRACT

A control method for a laundry treatment apparatus, which includes a first reservoir configured to hold water and defining a first opening to receive laundry therethrough, a second reservoir placed inside the first reservoir and defining a second opening, and a pulsator rotatably provided inside the second reservoir, includes supplying water to the first reservoir and performing primary washing of the first and second reservoirs by rotating at least one of the pulsator or the second reservoir. The primary washing step includes performing a first motion by rotating the pulsator to produce a water stream inside the first and second reservoirs, and performing a second motion by rotating the second reservoir to cause water to move upward along a space between an inner circumferential surface of the first reservoir and an outer circumferential surface of the second reservoir and then be introduced into the second reservoir through the second opening.

This application claims the benefit of Korean Patent Application No. 10-2015-0125007, filed on Sep. 3, 2015, which is hereby incorporated by reference as if fully set forth herein.

FIELD

The present disclosure relates to a control method for a laundry treatment apparatus.

BACKGROUND

A laundry treatment apparatus can include a cabinet defining the external appearance of the apparatus, a tub placed inside the cabinet and configured to store water therein, and a drum rotatably placed inside the tub and configured to receive laundry therein.

The laundry treatment apparatus having the above-described configuration is adapted to wash laundry using, for example, the emulsification of detergent and water streams produced by rotation of the drum. In some cases, impurities may adhere to the inside of the tub and the outer circumferential surface of the drum after long-term use of the laundry treatment apparatus.

SUMMARY

According to one aspect, a control method for a laundry treatment apparatus—where the laundry treatment apparatus includes a first reservoir placed inside a cabinet, the first reservoir being configured to hold water and defining a first opening configured to receive laundry therethrough, a second reservoir placed inside the first reservoir and configured to rotate about a rotating shaft perpendicular to a bottom surface of the first reservoir, the second reservoir being configured to receive laundry therein and defining a second opening, the second opening being located under the first opening, and a pulsator rotatably provided inside the second reservoir—includes supplying water to the first reservoir and performing primary washing of the first reservoir and the second reservoir by rotating at least one of the pulsator or the second reservoir. The primary washing step includes performing a first motion by rotating the pulsator to thereby produce a water stream inside the first and second reservoirs and performing a second motion by rotating the second reservoir to thereby cause water to move upward along a space between an inner circumferential surface of the first reservoir and an outer circumferential surface of the second reservoir and then to be introduced into the second reservoir through the second opening.

Implementations according to this aspect may include one or more of the following features. For example, the primary washing step may be initiated only when no laundry is in the first reservoir. The first motion and the second motion may be alternately repeated. The primary washing step may be implemented as a sequence where the first motion is followed by the second motion. The primary washing step may be implemented as a sequence where the second motion is followed by the first motion. The primary washing step may be implemented as a sequence where the second motion is followed by the first motion and then followed by the second motion.

In some cases, the control method may further include performing secondary washing of the first reservoir and the second reservoir after completion of the primary washing step, where the secondary washing step may include spraying water that is supplied from a water source to an inside of the second reservoir, discharging the sprayed water in the second reservoir to an outside of the first reservoir, and rotating the second reservoir. The secondary washing step may include implementing the spraying, the discharging, and the rotating steps simultaneously. Additionally, the control method may further include draining the water stored in the first reservoir after completion of the primary washing step, wherein the secondary washing step may be initiated after completion of the draining step. In some cases, the control method may further include dehydrating the second reservoir by rotating the second reservoir after completion of the secondary washing step. The spraying may be performed via a sprayer that is configured to spray water supplied from the water source to the circumferential surface of the second reservoir. The spraying may be performed via a sprayer that is configured to spray water to the circumferential surface of the second reservoir and a bottom surface of the second reservoir. The spraying step may include spraying water to cover a region ranging from a first point to a second point, the first point being located between a corner at which the circumferential surface of the second reservoir and a bottom surface of the second reservoir meet each other and a center of rotation of the second reservoir, and the second point being located between the corner and the second opening. The spraying may be performed via a connection pipe and a nozzle, the connection pipe being secured to the cabinet and connected to the water source, and the nozzle being configured to spray the water supplied from the connection pipe to the circumferential surface of the second reservoir and a bottom surface of the second reservoir, a cross sectional area of the nozzle increasing with increasing distance from the connection pipe.

According to another aspect, a control method for a laundry treatment apparatus—where the laundry treatment apparatus includes a first reservoir placed inside a cabinet, the first reservoir being configured to hold water and defining a first opening configured to receive laundry therethrough, a second reservoir placed inside the first reservoir and configured to rotate about a rotating shaft perpendicular to a bottom surface of the first reservoir, the second reservoir being configured to receive laundry therein and defining a second opening, the second opening being located under the first opening, and a pulsator rotatably provided inside the second reservoir—includes supplying water to the first reservoir, performing primary washing of the first reservoir and the second reservoir by rotating the pulsator so as to produce a water stream, and performing secondary washing of the first reservoir and the second reservoir after completion of the primary washing step. The secondary washing step includes spraying water, supplied from a water source, to an inside of the second reservoir, discharging the water inside the first reservoir to an outside of the first reservoir, and rotating the second reservoir.

Implementations according to this aspect may include one or more of the following features. For example, the secondary washing step may include implementing the spraying, the discharging, and the rotating steps simultaneously. The spraying may be performed via a sprayer configured to spray water to the circumferential surface of the second reservoir and a bottom surface of the second reservoir. In some cases, the spraying may be performed via a connection pipe and a nozzle, the connection pipe being secured to the cabinet and connected to the water source, and the nozzle being configured to spray the water supplied from the connection pipe to the circumferential surface of the second reservoir and a bottom surface of the second reservoir, a cross sectional area of the nozzle increasing with increasing distance from the connection pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a partial cross-sectional view illustrating an exemplary laundry treatment apparatus;

FIG. 2 is a partial cross-sectional view illustrating an exemplary cover;

FIG. 3 is a schematic view illustrating an exemplary sprayer;

FIG. 4 is a flowchart illustrating an exemplary control method for a laundry treatment apparatus;

FIGS. 5 and 6 are schematic views illustrating a first motion and a second motion, respectively, of an exemplary primary reservoir washing operation; and

FIG. 7 is a schematic view illustrating an exemplary secondary reservoir washing operation.

DETAILED DESCRIPTION

FIG. 1 shows an exemplary laundry treatment apparatus 100 according to one implementation. The laundry treatment apparatus 100 may include a cabinet 1, a first reservoir 3 which is placed inside the cabinet 1 and configured to store water therein, a second reservoir 5 which is rotatably placed inside the first reservoir 3 and configured to receive laundry therein, and a pulsator (or an agitator) 6 which is rotatably provided inside the second reservoir 5 so as to produce a water stream.

The cabinet 1 may include a cabinet body 11 which provides a space in which the first reservoir 3 is received, and a cabinet cover 12 provided at the top of the cabinet body 11.

The cabinet cover 12 has a cabinet opening 121, through which laundry may be introduced into or removed from the cabinet 1. The cabinet opening 121 may be opened or closed by a door 13 provided at the cabinet cover 12.

In addition, the cabinet cover 12 may be further provided with an input unit 17 which allows a user to input a control command to the laundry treatment apparatus 100, and a display unit 19 which allows the user to check the control command input via the input unit 17 or may indicate, for example, the implementation of the control command input by the user.

The first reservoir 3 may include a first body 31 which provides a space in which water is stored. The first body 31 may be secured to the cabinet body 11 using a support unit 15. The support unit 15 may be configured to alleviate vibration when the first body 31 vibrates.

The first body 31 may take the form of a cylinder having an open top, and a cover 33 may be provided at the top of the first body 31. As exemplarily illustrated in FIG. 2, the cover 33 may include a first opening 35 which can fluidically communicate with the cabinet opening 121, and a plurality of guides 37 which extend from the edge of the cover 33 toward the first opening 35. The guides 37 may serve to effectively perform a motion which rotates the second reservoir 5 to produce a predetermined form of water stream within the first reservoir 3. This will be described below in detail.

As further illustrated in FIG. 1, the second reservoir 5 may include a second body 51 which is placed inside the first reservoir 3 and provides a space in which laundry is received. The second body 51 may take the form of an empty cylinder. The second body 51 may fluidically communicate with the first opening 35 and the cabinet opening 121 via a second opening 53.

The second body 51 may include through-holes 55 that are defined in at least one of the circumferential surface or the bottom surface thereof. As such, the through-holes 55 may allow water inside the second body 51 to move to the first body 31 therethrough, and may allow water supplied to the first body 31 to be supplied into the second body 51 therethrough.

The second body 51 described above may be adapted to be rotated by a drive unit 57. The drive unit 57 may include a stator 571 secured to the bottom surface of the first body 31 so as to be located outside the first body 31, a rotor 573 configured to be rotated by a rotational magnetic field provided by the stator 571, and a rotating shaft 575 penetrating the first body 31 to connect the bottom surface of the second body 51 and the rotor 573 to each other.

FIG. 1 illustrates, as an example, the case where the rotating shaft 575 is perpendicular to the bottom surface of the first body 31. In this case, the second opening 53 is formed in the top of the second body 51.

The pulsator 6 may include a pulsator body (or an agitator body) 61 rotatably provided inside the second body 51 and a pulsator drive unit (or an agitator drive unit) to rotate the pulsator body 61.

The pulsator drive unit may include a second stator 63 configured to create a rotational magnetic field upon receiving current, a second rotor 65 configured to be rotated by the rotational magnetic field provided by the second stator 63, and a second rotating shaft 67 configured to connect the pulsator body 61 and the second rotor 65 to each other.

In this case, the second rotating shaft 67 may be inserted into a shaft through-hole 577, which is formed through the rotating shaft 575 of the second reservoir 5 (i.e. formed in the longitudinal direction of the rotating shaft 575), thereby connecting the pulsator body 61 and the second rotor 65 to each other.

In order to prevent the pulsator drive unit from interfering with the drive unit 57 of the second reservoir 5, a bracket 69 may further be provided at the bottom surface of the first body 31 so that the second stator 63 is secured to the bracket 69.

Accordingly, the laundry treatment apparatus 100 may rotate the second body 51 and the pulsator body 61 at the same time, or may rotate any one of the second body 51 and the pulsator body 61. The drive unit 57 and the pulsator drive unit 63, 65 and 67 may have any of various configurations so long as the above-described effects can be realized.

The laundry treatment apparatus 100 having the above-described configuration may be adapted to supply water to the first reservoir 3 using a water supply unit and to discharge the water inside the first reservoir 3 to the outside of the cabinet 1 using a drain unit.

The water supply unit may include a first supply pipe 71 connected to a water source to supply water to the first body 31, and a value 77 to open or close the first supply pipe 71. The drain unit may include a drain pipe 81 to guide the water inside the first body 31 to the outside of the cabinet 1, and a pump 83 to move the water inside the first body 31 to the drain pipe 81.

In addition, the laundry treatment apparatus 100 of the present invention may further include a sprayer 9 which sprays (or ejects) water, supplied from the water source, to the inside of the second body 51. As exemplarily illustrated in FIG. 3, the sprayer 9 may include a connection pipe 93 secured to the cabinet cover 12 and a nozzle 91 configured to spray water supplied from the connection pipe 93 to the inside of the second body 51.

The connection pipe 93 may directly receive water from the water source, or may receive water through a second supply pipe 75 that diverges from the first supply pipe 71. In the latter case, the valve 77 may be located at the point at which the first supply pipe 71 and the second supply pipe 75 diverge so as to control the opening or closing of the first supply pipe 71 and the second supply pipe 75.

The nozzle 91 may be provided at the edge of the cabinet opening 121 at a position spaced apart, by a prescribed distance, from a virtual line L1 which passes through the rotating shaft 575 of the second body 51 and may be perpendicular to the rear surface of the cabinet 1 (or the front surface of the cabinet 1).

The nozzle 91 may be located at any of the front side and the rear side of a virtual line L2 which passes through the rotating shaft 575 and may be perpendicular to the side surface of the cabinet 1. FIG. 3 illustrates the exemplary case where the nozzle 91 is located at the rear side of the virtual line L2. In this case, the length of the second supply pipe 75 may be minimized, which may minimize loss in the pressure of water sprayed from the nozzle 91.

In some cases, the nozzle 91 may be provided to spray water, supplied from the water source, only to the circumferential surface of the second body 51, and may be provided to spray water to the corner at which the circumferential surface and the bottom surface of the second body 51 meet each other.

In the case where the nozzle 91 is provided to spray water to the corner of the second body 51, the water spraying range of the nozzle 91 may be set to a region from a first point (P1, see FIG. 7), which is located between the corner and the rotating shaft 575 of the second body 51, to a second point (P2, see FIG. 7) which is located between the corner and the second opening 53.

To realize the spraying range of the nozzle 91 described above, the cross sectional area of the nozzle 91 may increase with increasing distance from the connection pipe 93.

FIG. 4 shows an exemplary control method of a laundry treatment apparatus for the washing of the first reservoir and the second reservoir. The control method of FIG. 4 may be implemented by a controller according to whether the number of times the laundry treatment apparatus is being operated or the operating duration of the laundry treatment apparatus is a reference value or more, or may be implemented only when the user requests that the reservoirs be washed. In the latter case, after it is judged whether the user requests the execution of a reservoir washing course via the input unit 17 (S10), the control method of FIG. 4 may be implemented only upon judging that a reservoir washing course command is input.

The controller may judge that the user requests the execution of the reservoir washing course when the user selects the reservoir washing course via the input unit 17 as well as when the user selects a course including the reservoir washing course via the input unit 17.

In some cases, the control method of FIG. 4 may be implemented in the state in which laundry is stored in the second reservoir 5. However, in consideration of the fact that the control method is intended to remove impurities remaining in the reservoirs 3 and 5, the control method of the present invention is generally implemented in the state in which no laundry is introduced into the second reservoir 5.

When it is attempted to implement the control method of FIG. 4 in the state in which no laundry is introduced into the second reservoir 5, the control method of the present invention may further include displaying a message, which inquires whether laundry is present in the second reservoir 5, on the display unit 19 when the user selects a reservoir washing course.

In the case where an operation of displaying the message inquiring whether the laundry is present in the second reservoir 5 is included, the control method of FIG. 4 may be implemented only in response to the input of a control signal indicating that no laundry is present in the second reservoir 5.

The signal indicating that no laundry is present in the second reservoir 5 may be input in various manners. That is, examples of the input method may include a method in which the user inputs, using the input unit 17, a control signal confirming that no laundry is present in the second reservoir 5, and a method in which the controller compares the magnitude of current supplied to the stator 571 with reference data when the second body 51 is rotated at predetermined revolutions per minute.

When the user selects the reservoir washing course or the course including the reservoir washing course, the control method may then proceed to an operation of supplying water to the first reservoir 3 using the water supply unit (S20). The operation of supplying water (S20) may be implemented as water is supplied to the first reservoir 3 through the supply pipe 71.

Once a desired amount of water has been supplied to the first reservoir 3 via the operation of supplying water (S20), the control method may then proceed to a primary reservoir washing operation S30 for washing the reservoirs 3 and 5 by producing a water stream.

The primary reservoir washing operation S30 may be implemented via the combination of a first motion, which rotates the pulsator body 61 to produce a water stream, and a second motion which rotates the second body 51 to produce a water stream.

As exemplarily illustrated in FIG. 5, the first motion (referred to as an “agitation motion”) is a motion that produces a water stream to move water from the bottom surface of the first body 31 to the top of the first body 31. To perform the first motion, the controller may control the alternate implementation of clockwise rotation and counterclockwise rotation of the pulsator body 61.

In the case of the laundry treatment apparatus in which the rotating shaft 575 of the second body 51 and the bottom surface of the first body 31 form a right angle and the second opening 53 for the introduction and removal of laundry is formed in the top of the second body 51, there may be a high likelihood that impurities such as detergents or contaminants separated from laundry, may adhere to the bottom surface of the second body 51 and the bottom surface of the first body 31.

Since the first motion is a motion that maintains a water stream moving from the bottom surface of the first body 31 to the first opening 35, the first motion may be referred to as a motion that produces a water stream suitable for the separation of impurities adhered to the bottom surface of the first body 31 and the bottom surface of the second body 51.

As exemplarily illustrated in FIG. 6, the second motion (referred to as a “wave force motion”) is a motion that produces a water stream to cause water, discharged out of the second body 51, to move upward along a space between the inner circumferential surface of the first body 31 and the outer circumferential surface of the second body 51 and thereafter be reintroduced into the second body 51 through the second opening 53.

To perform the second motion, the controller may rotate only the second body 51, or may rotate the second body 51 and the pulsator body 61 in the same direction at the same time. Hereinafter, the case where the second motion includes the simultaneous rotation of the second body 51 and the pulsator body 61 will be described.

When the second body 51 and the pulsator body 61 are rotated in the same direction at the same time, water moves to the cover 33 of the first body 31 along the space between the inner circumferential surface of the first body 31 and the outer circumferential surface of the second body 51 due to centrifugal force.

Owing to the guides 37 provided at the cover 33 that extend from the edge of the cover 33 toward the first opening 35, the water directed to the cover 33 by centrifugal force may move to the first opening 35 under the guidance of the guides 37, and may then be introduced into the second body 51 through the second opening 53 which is located under the first opening 35.

Since the second motion is a motion that maintains a water stream to cause water to move upward from the bottom surface of the first body 31 to the cover 33 and then be introduced into the second body 51, the water stream produced by the second motion may be suitable for the separation of impurities adhered to the bottom surface of the first body 31 and the bottom surface of the second body 51 as well as for the separation of impurities adhered to the circumferential surface of the first body 31 and the circumferential surface of the second body 51.

With regard to the second motion, the washing force, which is required to separate the impurities from the first body 31 and the second body 51, should increase as the flow rate of the water stream moving along the space between the inner circumferential surface of the first body 31 and the outer circumferential surface of the second body 51 increases. Accordingly, to perform the second motion, the controller may control the second body 51 and the pulsator body 61 so that they are rotated in the same direction, and the number of revolutions per minute of the second motion may be set to be higher than the number of revolutions per minute of the first motion.

In the primary reservoir washing operation S30, the first motion and the second motion may be alternately performed. That is, in the primary reservoir washing operation S30, the first motion may first be performed and then the second motion may be performed, or the second motion may first be performed and then the first motion may be performed.

The number of revolutions per minute of the second body 51 and the pulsator body 61 in the second motion may be higher than the number of revolutions per minute of the pulsator body 61 in the first motion. Therefore, performing first the first motion and then the second motion may be advantageous because it reduces the load on the drive unit 57 and the pulsator drive unit 63, 65 and 67.

In addition, the primary reservoir washing operation S30 may be implemented in the sequence of the second motion, the first motion, and the second motion. Since the washing force and washing range of the second motion are higher and wider than those of the first motion, implementing a greater number of repetitions of the second motion than the first motion may be advantageous for the washing of the reservoirs 3 and 5. However, since the load on the drive unit 57 and the pulsator drive unit 63, 65 and 67 should increase in the case where only the second motion is performed, sequentially repeating the second motion, the first motion, and the second motion may be advantageous in order to enhance washing force and to control the load of the drive units.

After completion of the primary reservoir washing operation S30, the control method proceeds to an operation of discharging the water stored in the first body 31 to the outside of the cabinet 1 via the drain unit (S40, a primary drainage operation).

In the primary drainage operation S40, the impurities, separated from the respective bodies 31 and 51 in the primary reservoir washing operation S30, are discharged outward, along with the water inside the first body 31, through the drain pipe 81 connected to the bottom surface of the first body 31.

However, some of the impurities separated from the first body 31 and the second body 51 in the primary reservoir washing operation S30 may remain on the respective bodies 31 and 51, rather than being completely discharged via the primary drainage operation S40.

In order to prevent the impurities from remaining on the bodies 31 and 51, after completion of the primary drainage operation S40, the control method proceeds to a secondary reservoir washing operation S50 of spraying water using the sprayer 9.

The secondary reservoir washing operation S50 (referred to a “jet spray motion”) is an operation of additionally washing the reservoirs 3 and 5 and discharging the impurities, separated from the surfaces of the respective reservoirs 3 and 5 in the primary reservoir washing operation S30, to the outside of the first body 31 (i.e. rinsing).

The secondary reservoir washing operation S50 may include spraying water into the second body 51 using the sprayer 9 (S53), discharging the water, sprayed from the sprayer 9, to the outside of the first body 31 (S55, a secondary drainage operation), and rotating the second body 51 (S51).

In order to minimize the amount of impurities that remain in the reservoirs 3 and 5, the spraying operation S53 and the secondary drainage operation S55 may be implemented at the same time. That is, the secondary reservoir washing operation S50 may include a time period during which the spraying operation S53 and the secondary drainage operation S55 are performed at the same time (in terms of rinsing performance enhancement).

In some cases, the sprayer 9 is configured to spray water only to a given region of the second body 51, and therefore, the rotating operation S51 serves to minimize the amount of impurities that remain on the second body 51 in consideration of the fixed spraying range of the sprayer 9.

In addition, since the rotating operation S51 applies centrifugal force to the water discharged from the second body 51 to the first body 31 through the through-holes 55, the water supplied from the sprayer 9 to the second body 51 may hit the surface of the first body 31. Accordingly, the rotating operation S51 serves not only to enhance rinsing performance, but also to enhance the washing performance of the reservoirs 3 and 5. In the rotating operation S51, the number of revolutions per minute of the second body 51 may be set to be lower than the number of revolutions per minute of the first motion and the number of revolutions per minute of the second motion.

To realize the effects described above, the secondary reservoir washing operation S50 may include a time period during which the spraying operation S53, the secondary drainage operation S55, and the rotating operation S51 are performed at the same time.

As exemplarily illustrated in FIG. 7, the sprayer 9 may be configured to spray water only to the circumferential surface of the second body 51, may be configured to spray water only to the bottom surface of the second body 51, or may be configured to spray water to both the circumferential surface and the bottom surface of the second body 51.

In the case where the sprayer 9 sprays water to the circumferential surface C1 of the second body 51, the water may be sprayed to a height higher than a given position on the circumferential surface C1, according to the number of revolutions per minute of the second body 51, the water sprayed to the vicinity of the second opening 53 may occasionally be discharged out of the second body 51 through the second opening 53, rather than being used to hit the inner circumferential surface of the first body 31 by passing through the through-holes 55.

In the case where the sprayer 9 is configured to spray water to both the circumferential surface C1 and the bottom surface C2 of the second body 51, the sprayer 9 may be adapted to spray water to a range from the first point P1, which is located between the corner of the second body 51 (i.e. the point at which the circumferential surface C1 and the bottom surface C2 meet each other) and the center of rotation of the second body 51 (i.e. the rotating shaft 575), to the second point P2, which is located between the corner and the second opening 53.

As shown in FIG. 4, after completion of the secondary reservoir washing operation S50, the control method proceeds to a dehydration operation S60 to minimize the amount of water remaining in the second body 51.

In the dehydration operation S60, only the second body 51 may be rotated, or both the second body 51 and the pulsator body 61 may be rotated together.

In some implementations, at least one of the first drainage operation S40 and the dehydration operation S60 may be omitted. This is because the second drainage operation S55 included in the secondary reservoir washing operation S50 may substitute for the first drainage operation S40 and the rotating operation S51 may substitute for the dehydration operation S60.

That is, when the secondary reservoir washing operation S50 includes a time period during which the secondary drainage operation S55, the rotating operation S51, and the spraying operation S53 are performed at the same time, and the sprayer 9 and the drain unit are controlled such that the flow rate of water drained in the second drainage operation S55 is greater than the flow rate of water supplied in the spraying operation S53, the water used in the primary reservoir washing operation S30 may be drained even if the primary drainage operation S40 is omitted.

Meanwhile, the secondary drainage operation S55, the rotating operation S51, and the spraying operation S53 may be performed at the same time for a given time period, and after the spraying step S53 ends, only the rotating operation S51 and the secondary drainage operation S55 are maintained. In this way, it may be possible to minimize the amount of water that remains in the reservoirs 3 and 5 even if the dehydration operation S60 is omitted.

In some implementations, the primary reservoir washing operation S30 may include only the first motion that rotates the pulsator 6 to produce a water stream. In this case, in the control method of the present invention, the secondary reservoir washing operation S50 may be performed after the first motion ends. In the case where the primary reservoir washing operation S30 does not include the second motion, the implementation time of the secondary reservoir washing operation S50 may increase, or the number of revolutions per minute of the second body 51 (or the second body 51 and the pulsator body 61) that is rotated in the rotating operation S51 may increase.

The primary reservoir washing operation S30, the primary drainage operation S40, the secondary reservoir washing operation S50, and the dehydration operation S60 may be implemented in sequence.

However, since the primary drainage operation S40 may be replaced with the secondary drainage operation S55 included in the secondary reservoir washing operation S50 and the dehydration operation S60 may be replaced with the rotating operation S51 of the secondary reservoir washing operation S50, in the control method according to the present implementation, the water supply operation S20, the primary reservoir washing operation S30, and the secondary reservoir washing operation S60 may be implemented in sequence.

As is apparent from the above description, the present disclosure may help realize the effect of providing and controlling a laundry treatment apparatus to enable the washing of a first reservoir in which water is stored and a second reservoir in which laundry is stored.

In addition, the present disclosure may help realize the effect of providing and controlling a laundry treatment apparatus that implements the washing of a first reservoir and a second reservoir via a wave force motion which rotates the second reservoir to cause water to move upward along a space between the inner circumferential surface of the first reservoir and the outer circumferential surface of the second reservoir, and thereafter be introduced into the second reservoir.

In addition, the present disclosure may help realize the effect of providing and controlling a laundry treatment apparatus that implements the washing of a first reservoir and a second reservoir via a motion which rotates a pulsator provided inside the second reservoir to produce water streams.

In addition, the present disclosure may help realize the effect of providing and controlling a laundry treatment apparatus that implements the washing of a first reservoir and a second reservoir via a jet spray motion which sprays water into the second reservoir while the second reservoir is rotated.

Although example implementations have been illustrated and described above, it will be apparent to those skilled in the art that the implementations are provided to assist understanding of the present disclosure. The present disclosure is not limited to the above described particular implementations, and various modifications and variations can be made in the present disclosure without departing from the spirit or scope of the present disclosure. 

What is claimed is:
 1. A control method for a laundry treatment apparatus, the laundry treatment apparatus comprising a first reservoir placed inside a cabinet, the first reservoir being configured to hold water and defining a first opening configured to receive laundry therethrough, a second reservoir placed inside the first reservoir and configured to rotate about a rotating shaft perpendicular to a bottom surface of the first reservoir, the second reservoir being configured to receive laundry therein and defining a second opening, the second opening being located under the first opening, and a pulsator rotatably provided inside the second reservoir, the control method comprising: supplying water to the first reservoir; and performing primary washing of the first reservoir and the second reservoir by rotating at least one of the pulsator or the second reservoir, wherein the primary washing step includes: performing a first motion by rotating the pulsator to thereby produce a water stream inside the first and second reservoirs, and performing a second motion by rotating the second reservoir to thereby cause water to move upward along a space between an inner circumferential surface of the first reservoir and an outer circumferential surface of the second reservoir and then to be introduced into the second reservoir through the second opening.
 2. The control method according to claim 1, wherein the primary washing step is initiated only when no laundry is in the first reservoir.
 3. The control method according to claim 1, wherein the first motion and the second motion are alternately repeated.
 4. The control method according to claim 1, wherein the primary washing step is implemented as a sequence where the first motion is followed by the second motion.
 5. The control method according to claim 1, wherein the primary washing step is implemented as a sequence where the second motion is followed by the first motion.
 6. The control method according to claim 1, wherein the primary washing step is implemented as a sequence where the second motion is followed by the first motion and then followed by the second motion.
 7. The control method according to claim 1, further comprising performing secondary washing of the first reservoir and the second reservoir after completion of the primary washing step, wherein the secondary washing step includes: spraying water that is supplied from a water source to an inside of the second reservoir; discharging the sprayed water in the second reservoir to an outside of the first reservoir; and rotating the second reservoir.
 8. The control method according to claim 7, wherein the secondary washing step includes implementing the spraying, the discharging, and the rotating steps simultaneously.
 9. The control method according to claim 7, further comprising draining the water stored in the first reservoir after completion of the primary washing step, wherein the secondary washing step is initiated after completion of the draining step.
 10. The control method according to claim 7, further comprising dehydrating the second reservoir by rotating the second reservoir after completion of the secondary washing step.
 11. The control method according to claim 7, wherein the spraying is performed via a sprayer that is configured to spray water supplied from the water source to the circumferential surface of the second reservoir.
 12. The control method according to claim 7, wherein the spraying is performed via a sprayer that is configured to spray water to the circumferential surface of the second reservoir and a bottom surface of the second reservoir.
 13. The control method according to claim 7, wherein the spraying step includes spraying water to cover a region ranging from a first point to a second point, the first point being located between a corner at which the circumferential surface of the second reservoir and a bottom surface of the second reservoir meet each other and a center of rotation of the second reservoir, and the second point being located between the corner and the second opening.
 14. The control method according to claim 7, wherein the spraying is performed via a connection pipe and a nozzle, the connection pipe being secured to the cabinet and connected to the water source, and the nozzle being configured to spray the water supplied from the connection pipe to the circumferential surface of the second reservoir and a bottom surface of the second reservoir, a cross sectional area of the nozzle increasing with increasing distance from the connection pipe.
 15. A control method for a laundry treatment apparatus, the laundry treatment apparatus comprising a first reservoir placed inside a cabinet, the first reservoir being configured to hold water and defining a first opening configured to receive laundry therethrough, a second reservoir placed inside the first reservoir and configured to rotate about a rotating shaft perpendicular to a bottom surface of the first reservoir, the second reservoir being configured to receive laundry therein and defining a second opening, the second opening being located under the first opening, and a pulsator rotatably provided inside the second reservoir, the control method comprising: supplying water to the first reservoir; performing primary washing of the first reservoir and the second reservoir by rotating the pulsator so as to produce a water stream; and performing secondary washing of the first reservoir and the second reservoir after completion of the primary washing step, wherein the secondary washing step includes: spraying water, supplied from a water source, to an inside of the second reservoir, discharging the water inside the first reservoir to an outside of the first reservoir, and rotating the second reservoir.
 16. The control method according to claim 15, wherein the secondary washing step includes implementing the spraying, the discharging, and the rotating steps simultaneously.
 17. The control method according to claim 15, wherein the spraying is performed via a sprayer configured to spray water to the circumferential surface of the second reservoir and a bottom surface of the second reservoir.
 18. The control method according to claim 15, wherein the spraying is performed via a connection pipe and a nozzle, the connection pipe being secured to the cabinet and connected to the water source, and the nozzle being configured to spray the water supplied from the connection pipe to the circumferential surface of the second reservoir and a bottom surface of the second reservoir, a cross sectional area of the nozzle increasing with increasing distance from the connection pipe. 